Treatment of tobacco



Patented Feb. 4, 1936 UNITED STATES PATENT OFFICE Bert Loewenthal, NewYork, N. Y., assignor to Federal Tobacco Corporation, a corporation ofNew York No Drawing.

Application February 13, 1933,

Serial No. 656,595

25 Claims.

This invention relates to the treatment of tobacco. It includes newmethods of treating tobacco to improve its appearance and smokingqualities and includes the new products produced.

According to this invention gums, oils, nicotine and mineral matter areremoved from the leaves which are then impregnated with organic matterand mineral matter to give the tobacco the proper 0 fiavor and burningproperties. I find that by treatment for a short time in a hot nitricacid bath the gum can be quickly removed and by subjecting a leafsuitable for a cigar wrapper to such treatment I obtain a product whichis light and uniform in color and which on impregnation with a properlycolored solution yields a leaf in every way suitable for use as a cigarwrapper. By treating dark or gummy leaves in this way I obtain wrapperswhicn are superior in both appearance and smoking qualities I dip thetobacco in a hot bath of nitric acid and I prefer toleav the tobacco inthe bath until substantially all of the gum and also mineral matter,oils ar d nicotine have been dissolved 5 out of the leaf. I find itadvantageous to add a substance such as phosphoric acid to the treatingbath, to prevent the nitric acid from staining the woody and starchycomponents yellow, and I prefer to use phosphoric acid because it colorsthem a greenish shade. After the acid treatment, the tobacco isthoroughly washed andpreferably then treated in a neutralizing bath suchas a lime bath. After the lime treatment, I find it desirable to dry thetobacco before impregnating it with mineral salts and organic materialswhich give the tobacco the proper flavor, aroma, and burning qualities.The impregnating solution is referred to herein as the burning solution.After treating the tobacco in the burning solution, it is preferablysubjected to a glycerine treatment and then dried.

In preparing leaves for use as wrappers, care must be taken not to tearor otherwise injure them. Special handling apparatus may be employed forthis purpose. The process is of particular value in the treatment ofwrapper tobaccos such as Sumatra wrappers, Java wrappers, Connecticutshade-grown wrappers, Florida wrappers, Connecticut broad leaf wrappers,Kentucky wrappers and Ohio wrappers.

For example, in the treatment of Sumatra or Connecticut shade-grownwrappers, I load the leaves tied into bundles or hands, each containingabout 25m 30 leaves, into a backet so that the butts of the tobacco,that is, the stem ends of the leaves, are at the bottom when the basketis immersed in the acid bath, the tips of the leaves pointing upward. Inloading the tobacco into the basket, I do not crowd it but allowsufiicient access of the acid to the leaves to permit the removal of thegum from the color and other cells. Instead of using a basket, I mayattach the butt ends of the leaves or hands of tobacco to a plungerwhich is forced to the bottom of the bath, thus leaving the leaves freeto assume an upright position in the bath. Various means of insertingthe leaves into the acid bath may be employed.

I have used a bath containing seven percent of concentrated nitric acidwith a specific gravity of 1.42 and one percent of percent syrupyphosphoric acid. I heat the bath to preferably about to 180 F. andsubject the tobacco to the action of the bath for only a few minutes,for example from three to ten minutes, the time depending upon thestrength and temperature of the bath. The treatment is controlled so asto prevent the leaf from being weakened and rendered unsuitable for useas a wrapper. For S'matra wrappers, treatment in a bath of the abovecomposition at F. for about seven minutes is sulficient. All the gum isremoved from the leaves, together with mineral matter and the leavesbecome thin and light in color. On removing the leaves from the acidbath they are subjected immediately to washing, preferably first withwater and then with a base and with gradual reduction in the temperatureof the treating solutions to avoid closing the color and feeding cells.For example, the leaves may be first washed in a *ank of filtered waterkept at about 150 F. After staying in this bath for only about thirtyseconds, I remove them to another tank containing water at about 125 F.I prefer to keep this Water fresh by continuously adding fresh water toit and withdrawing used water from it. After about fifteen minutes orwhen the leaves are neutral to blue litmus paper pressed between them,they are removed to the lime bath. I find it advantageous to use a limebath containing about onehalf an ounce of oxide-of lime to three gallonsof water which is filtered to free it from any undissolved lime beforeit is used in the treatment of the tobacco. I soak the leaves five toten minutes in such a lime bath maintained at 125 F. to neutralize anyremaining acid.

The tobacco is then dried by placing it on racks in a drying room andkept at about 110 F. until dry, that is, until the leaves have not morethan ten percent moisture.

The treated leaf at this stage of the treatment Consists essentially ofthe woody and starch components of the leaf covered with a fibrousskin-like layer. Substantially all of the gums, oils, nicotine andmineral matter including salts have been removed and the leaf isuniformly colored and of a yellowish woody color. This skeleton leafproduct may now be treated with various materials to impart the desiredcolor, fiavor and aroma to the tobacco and to give it the desiredsmoking and ashing properties.

The burning solution which I have found advantageous for the treatmentof Sumatra wrappers is made up principally of equal parts of thefollowing three solutions, and coloring matter and oils for flavoringmay be added as desired. The first solution is prepared by boilingtobacco stems in water. For example, I may take twenty gallons ofordinary Havana stems ground or cut to one inch or less in length andadd these to gallons of filtered water and after boiling for about threehours strain the liquid and cool it. It is advantageously strainedthrough about four layers of cheese cloth and one layer of absorbentcotton. I cool it to a temperature of about 70 F. and find that at thistemperature such a solution has a gravity of about 4.60 Baum. Solutionsof lower or higher gravity, such as 3.60 Baum or 5.35 Baum may be used.Various tobacco extracts of this sort having various concentrations oftobacco constituents may be employed to impart desirable properties tothe finished product. The compositions employed for this purpose mayvary in strength and composition and may be prepared from variousstarting materials and may be obtained by different methods oftreatment. I prefer to use Havana stems because they contain desirabledelicate flavoring and aroma producing materials.

The second and third solutions contain mineral matter to impart properburning and ashing properties to the finished product. One of thesebaths is prepared by adding sufllcient water to 6% ounces of potassiumacetate, 9 ounces of potassium nitrate and three pounds of calciumacetate to make two gallons of solution. The amount of minerals addedmay be varied and at times different minerals may be employed to impartthe required properties to a product. For example, the amount ofpotassium acetate may be varied between four to eight ounces, the amountof potassium nitrate between five and twelve ounces and the amount ofcalcium acetate from one to six pounds. For the third bath I use twoparts by weight of potassium carbonate dissolved in one hundred parts ofwater. Although I prefer to prepare the burning solution by mixing threeseparate solutions as described, the method of preparation andcomposition may be varied. I do not desire to be bound by the mineralshere named or.the amounts mentioned as I employ whatever minerals ofthis nature are necessary or desirable for a given product.

These three baths are then mixed in equal parts by weight and the leavesor hands after drying are saturated with the resulting solution. Thismay be done by soaking the leaves in the solution for a period of abouttwo hours starting the treatment at a temperature of F. and allowing itgradually to cool to 100 F. during the course of treatment. With burningsolutions of different temperature or concentration, different times oftreatment may be found to be desirable.

After treating with the burning solution, I find it advantageous to dipthe leaves in a glycerine bath containing one-half percent of glycerinein water. Treatment for twenty seconds in such a bath maintained at 65F. is satisfactory. After I the glycerine dip, the leaves are againplaced in the racks in the drying room for 1%, hours or until thetobacco shows ten percent moisture content. I

If the leaves are to be baled, I find it desirable to treat them in asteam room for about one-half hour or until the tobacco is thoroughlymoist before packing them.

somewhat by employing higher temperatures.

In some cases the treatment may be effected at a temperature as low asor F. but care must be taken not to weaken the wrappers and the gum mustbe entirely removed to form high grade wrappers which are unifo'i mlycolored. The heavier tobaccos which contain more gum require a moredrastic treatment than the lighter tobaccos.

The composition of the acid bath may be varied. I may, for example, usebut five percent nitric acid or acid more concentrated than sevenpercent. With concentrated acid a somewhat higher temperature would berequired.

I find that the color of the final product is improved by addingcoloring matter such as chlorophyl green to the burning solution beforetreating the leaves in it. A small amount of this green producesdesirable results. Malachite green or other coloring matter may beemployed. Various flavoring materials may be added to the burningsolution to modify the taste or other properties of the final product. i

In carrying out the acid treatment I use ceramic blending and mixingtanks or iron tanks coated with a heavy enamel which is free from allcracks, pin holes and similar imperfections. The acid must be kept outof contact with iron as iron .will give the tobacco a reddish cast whichis ordinarily undesirable. The burning solution, wash water and limewater may be handled in heavy cypress wood tanks containing suitableheating coils such as one-half inch brass coils placed near the bottomof the tank. A tank of galvanized iron or enamelware may be used forboiling the Havana stems. The baskets used for the acid dip should beenameled and those used in the burning solution or washing steps may beeither enameled wood or galvanized iron.

The drying room may be of any suitable construction. It should beprovided with air circulating means and suitable heating devices.

The steam room is advantageously kept at a temperature of about 90 F.and is continuously supplied with steam in sufficient quantity tomaintain a high water content per cubic foot.

After removing the gum and mineral matter from the tobacco, it may bestored or shipped to another plant for impregnation with burningsolution or it may be treated at the same plant.

I claim:

1. The method of preparing tobacco which comprises removing gum, oils,nicotine and mineral matter from the leaf in an acid bath containingnitric and phosphoric acids.

2. The method of preparing cigar wrappers which comprises removing oils,nicotine, mineral matter and substantially all the gum from a tobaccoleaf in a bath containing at least five percent nitric acid at atemperature of at least 155 F.

3. The method of treating tobacco leaves which comprises removing gumfrom the color cells in a hot bath and then gradually cooling thetobacco in one or more subsequent treating baths to avoid closing thecolor cells.

4. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves an alkalimetal salt of an organic acid, an alkali metal nitrate, an alkali metalcarbonate and an alkaline earth metal salt of an organic acid to improvethe burning properties of the leaves and a tobacco extract to improvethe flavor of the leaves.

5. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves an alkalimetal acetate, an alkali metal nitrate, an alkali metal carbonate and analkaline earth metal acetate to improve the burning qualities of theleaves and a tobacco extract'to improve the flavor of the leaves.

6. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves an alkalimetal salt of an organic acid to improve their burning qualities and atobacco extract to improve their flavor.

'1. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves analkaline earth metal salt of an organic acid to improve their burningproperties and a tobacco extract to improve their flavor.

8. The method of treating tobacco leaves which comprises removingundesirable natural substances from the-leaves without destroying theleaf structures, and subsequently incorporating in the leaves an alkalimetal acetate to improve their burning properties and a tobacco extractto improve their flavor.

9. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves analkaline earth metal acetate to improve their burning properties and atobacco .extract to improve their flavor.

10. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves an alkalimetal carbonate to improve their burning properties and a tobaccoextract to improve their flavor.

ll. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves a tobaccoextract to improve their flavor and potassium acetate to improve theirburning properties.

12. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves a tobaccoextract to improve their flavor and calcium acetate to improve theirburning properties.

13. The method of treating tobacco leaves which comprises removingundesirable natural substances from the leaves without destroying theleaf structures, and subsequently incorporating in the leaves a tobaccoextract to improve their flavor and potassium carbonate to improve theirburning properties.

14. The method of treating tobacco leaves to extract undesirable naturalsubstances which comprises immersing the leaves in"a dilute solution ofnitric acid at a temperature of about 155 to 185 F. for a period ofabout 3 to 10 minutes.

15. The method of treating tobacco leaves to extract undesirable naturalsubstances which comprises immersing the leaves in a solution containingabout 5 to 7 percent nitric acid at a temperature of about 155 to 185 F.for a period 'of about 3 to 10 minutes.

16. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith an alkali metal salt of an organic acid, an alkali metal nitrate,an alkali metal caronate and an alkaline earth metal salt of an organicacid to impart burning properties and a 18. A tobacco leaf from whichundesirable natural substances have been removed without destroying theleaf structure and which is impregnated with an alkali metal salt of anorganic acid to impart burning properties and a tobacco extract toimpart flavoring properties.

19. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith an alkaline earth metal salt of an organic acid to impart burningproperties and a tobacco extract to impart flavoring properties.

20. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith an alkali metal acetate to impart burning properties and a tobaccoextract to impart flavoring properties.

21. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith an alkaline earth metal acetate to impart burning properties and atobacco extract to impart flavoring properties.

22. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith an alkali metal carbonate to impart burning properties and atobacco extract to impart flavoring properties.

23. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith a tobacco extract to impart flavoring properties and potassiumacetate to impart burning properties,

24. A tobacco leaf from which undesirable natural substances have beenremoved without destroying the leaf structure and which is impregnatedwith a tobacco extract to impart flavoring properties and potassiumcarbonate to impart burning properties.

BERT LOEWENTHAL.

